Viessman F5 fault, not the usual suspect!

[mazperks]

Hi, my viess. 100 tripped out with an F5 fault.
'I'm not a heating engineer, but have managed to sort out a few breakdowns in the past with the help of this forum and I've read about the air flap valve problem.
However on taking the cover off, it had already been removed, (I recall having a call out under warranty three yrs ago so it must have been done then)
Anyway I turned to the air pressure switch, it has to be that I thought, yes its not making when I blow, then I realised it makes on suction. A check with the meter confirms its working fine. Also checked fan blades were actually turning and not just making a noise.
After much head scratching and calls from the wife to send for the cavalry, I almost gave in, but then I realised I couldnt actually hear the pressure sw operating, so I poked a straw in the air tube spigot on the fan housing and gave it a blow.
Eureka! on re connecting it fired up, so the big question--- was it just dirt
blocking it or is there some form of valve in that area that had stuck?
Anyone else come across this one.
Cheers Ian.

 

[petertheplumber12]

deleted by mod

 

[mazperks]

******** I wasn't sure ***********

 

[Agile]

in spite of the inappropriate advice which has been given by Pete, we do not advise DIYers to even open the combustion chamber and certainly not to interfere with the APS.

Tony

 

[Bunnyman]

It scares me when I read things like this. Hope u value ur family as much as ur wallet

 

[petertheplumber12]

in spite of the inappropriate advice which has been given by Pete, we do not advise DIYers to even open the combustion chamber and certainly not to interfere with the APS.

Tony

deleted by mod

 

[Dan Robinson]

But it is a pretty crucial safety device that the uninitiated should not be playing with.

Have you heard the phrase "more by luck than judgment"